Imaging technologies are widely used to study structures of materials in order to gain information about the materials' properties. In medical imaging, various imaging techniques are used for imaging structures of a subject. In particular, Computer Tomography (CT), Spectral CT, Positron Emission Tomography (PET), Single Photon Emission Computer Tomography (SPECT) are capable of imaging internal structures of a patient in a non-invasive manner.
In the afore-mentioned imaging techniques, particularly in CT and Spectral CT, the subject is irradiated by radiation signals, in particular X-rays, emitted by a radiation source, wherein the subject is irradiated in a plurality of directions. The radiation signals are transmitted through the irradiated subject, in which the radiation signals are partially absorbed and/or scattered. The transmitted radiation signals are subsequently detected by a sensor device, which is positioned on the opposite side of the radiation source with respect to the irradiated subject.
Depending on the specific imaging technique, the radiation signals may be photons of a specific wavelength or a plurality of wavelengths of a specific electromagnetic spectrum. For instance, X-ray-based imaging techniques including CT, mammography and fluoroscopy typically utilize an X-ray radiation source that emits X-rays, wherein the sensor device is configured to detect the X-rays transmitted through the subject. PET utilizes positrons, while SPECT utilizes gamma rays.
In order that the radiation signals or photons can be processed electronically, the sensor device is configured to convert the radiation signals received by the sensor device into corresponding electric signals that are processed by and/or directed to one or more electronic entities, such as an integrated circuit (IC) element, which enable and/or assist the generating of medical images.
It is desirable to obtain medical images which reflect the information about the irradiated subjects as completely as possible. For this purpose, photons transmitted through the irradiated subject in various directions need to be detected, counted and possibly discriminated by energy. (e.g. for Spectral CT). Furthermore, CT systems must provide a large area coverage for clinically relevant diagnosis. In addition, it is also desirable to obtain medical images with high image resolution, so that structural details with low dimensions are detectable. The sensor device comprises a plurality of detectors which form at least one sensor array. In particular, the detectors are arranged so that they are four-sidedly buttable, i.e. the detectors are placed adjacent to each other in various planar directions. In this way a CT sensor device can be built to offer sufficient coverage, i.e. being able to image a significant portion of the body (e.g. heart) in one single rotation.
Numerous sensor devices are known which provide the four-sided buttability. However, the sensor devices known in the field of imaging technologies are limited in signal integrity and cost efficiency.
U.S. Pat. No. 8,575,558 B2 discloses a detector array comprising a plurality of tileable sensor stacks arranged on a first side of a substrate to form a planar detector array, wherein each of the plurality of tileable sensor stacks comprises a detector, an integrated circuit and an interposer element, wherein the interposer element is disposed between the detector and the integrated circuit and configured to operationally couple the detector to the integrated circuit.
US 2010/327173 A1 discloses an integrated direct conversion detector module with a direct conversion crystal with an anode and cathode on opposite sides thereof, as well as an integrated circuit in electrical communication with the direct conversion crystal. A redistribution layer is deposited on the anode layer, which is configured to adapt a pad array layout of the direct conversion crystal to a predetermined lead pattern.